Yes, you can.
If it were me, here's what I'd do.
1) Create a simple empty app. Use the barebones template.
Once you have that created, you'll find that it provides the app but nothing else. This is OK.
2) Copy/move your dashboard's xml file into your new app's structure. Easiest way is to
2.1) Click Settings, User interface.
2.2) Click around in the various options and filtering to find the dashboard in the list.
2.3) On the dashboard's entry, click 'Clone'
2.4) In the new screen that pops up, change the app drop-down to the new app's name.
2.5) Do whatever else that screen tells you (Maybe nothing - I just am not doing it myself so I'm not sure if there's a confirmation)
3) SWITCH TO THE NEW APP if you aren't in it already.
4) Now change the new dashboard in that app to be the default dashboard for the app. Used to be you had to do this in the navigation view files, maybe you still do sort of, but here's an answers post with several methods that all seem ... reasonable?
https://answers.splunk.com/answers/368983/how-do-i-set-my-apps-start-view-to-be-the-dashboar.html
I hope this helps!
And happy splunking!
-Rich
